What is a CP2000 Notice?

An IRS Notice CP2000 is not an audit letter or a formal bill. Instead, it is an underreporter inquiry. For detailed assistance, see our IRS CP2000 Response Guide.

The IRS sends this notice when the income, payments, or credits reported on your tax return do not match the information reported to the IRS by third parties (like your bank, employer, or brokerage firm on Forms W-2, 1099, or 1099-R).

Step-by-Step Response Checklist

If you receive a CP2000 notice, follow these steps to review and respond:

  1. Do Not Panic: A CP2000 is a proposal, not a final tax assessment.
  2. Verify the Deadline: You typically have 30 days from the date printed on the notice to respond.
  3. Compare with Your Records: Check the “Proposed Changes” section of the notice against your tax returns and W-2 or 1099 worksheets, or utilize our IRS CP2000 response guide.
  4. Locate the Discrepancy: The notice will specify exactly which forms (e.g. 1099-INT, 1099-B) the IRS thinks are missing from your return.
  5. Decide if You Agree or Disagree:
    • If you agree: Sign the Response Form and send it back. The IRS will send you a formal bill.
    • If you disagree: Do not sign the agreement form. Instead, prepare a written response explaining why the notice is incorrect and provide supporting documentation.

📖 Real-Life Scenario

Responding to a CP2000 With Corrected Cost Basis Documentation

Barbara, 69 — Virginia Retired teacher | Investment account holder | CP2000 recipient

Barbara received a CP2000 notice proposing she owed $3,240 in additional taxes on $16,200 of unreported income. The IRS had received a 1099-B from her brokerage showing $16,200 in stock sale proceeds. Barbara had sold shares purchased 20 years ago for $14,800. Her tax software had used $0 as the cost basis, overstating her taxable gain. She gathered her original purchase confirmation statements proving a $14,800 basis, making her actual taxable gain only $1,400. She wrote a response letter to the IRS, attached the supporting documentation, and requested the proposed amount be corrected. The IRS adjusted the proposal, and her actual additional tax was $210 instead of $3,240.

Key Numbers in This Case:
  • Original CP2000 proposed amount: $3,240 in additional tax
  • Actual taxable gain after cost basis correction: $1,400 (vs. $16,200 proposed)
  • Barbara's actual additional tax liability: $210
  • Documentation used: original brokerage purchase confirmation from 20 years prior
  • Response deadline on CP2000: 60 days from the date on the notice
💡 Key Takeaway: A CP2000 is a computer-generated proposal, not a bill — always check the math before paying, because the IRS system frequently lacks the cost basis information needed to calculate your correct taxable gain.

Common Reasons for CP2000 Errors

Notice CP2000 letters are generated by automated systems and frequently contain errors. Common issues include:

  • Cost Basis Errors: The IRS receives a 1099-B for stock sales but assumes the cost basis was $0, calculating a tax penalty on the entire sale price instead of the net profit.
  • Pension Rollovers: You rolled over a retirement account (like an IRA) to another tax-deferred account. The IRS sees a 1099-R distribution but misses the rollover deposit proof.
  • Double Reporting: The same income was reported under a different category or employer ID.

⚠️ Common Mistakes to Avoid

❌ Mistake 1: Paying the CP2000 Proposed Amount Without Verifying the Calculation

The most expensive mistake when receiving a CP2000 is treating it as a final tax bill and paying immediately without investigation. A CP2000 is generated by an automated IRS matching system that compares third-party 1099s to your return. The IRS system does not have access to your investment cost basis, your offsetting deductions, or the context behind the apparent discrepancy. Many CP2000 amounts are significantly overstated.

✅ What to Do Instead:
  • Do not pay the proposed amount until you have compared it against your own tax return and confirmed whether the income was already reported correctly.
  • Gather all documentation: 1099s, brokerage statements, original purchase confirmations, and your filed tax return for the relevant year.
  • If you agree only partially with the CP2000, check the box indicating partial agreement, calculate the correct amount, and send your documentation with a detailed explanation.

❌ Mistake 2: Ignoring the CP2000 Notice and Missing the 60-Day Response Deadline

A CP2000 notice provides 60 days to respond. If you do not respond within that window, the IRS will send a Notice of Deficiency (CP3219A), which begins a different and much more formal process. The longer you wait, the more the proposed amount may grow as interest accumulates (currently 8% per year for individual taxpayers), and your appeal options become more limited.

✅ What to Do Instead:
  • Mark the response deadline on your calendar the day the notice arrives — it is printed clearly on the top right of the CP2000.
  • If you need more time to gather documentation, call the IRS at the number on the notice and request a 60-day extension — extensions are routinely granted for CP2000 responses.
  • If you are uncertain how to respond, contact a CPA or IRS Enrolled Agent — many offer a flat-fee CP2000 response service that is far less expensive than paying an overstated bill.

❌ Mistake 3: Not Keeping Records of Investment Cost Basis for Long-Term Holdings

Many seniors with long-held investments — stocks, mutual funds, or inherited securities — do not have clear records of their original purchase price. When these assets are eventually sold, brokerage firms may report $0 or "unknown" cost basis on the 1099-B, leading the IRS to treat the entire sale proceeds as taxable gain. The resulting CP2000 can be massive relative to the actual taxable amount.

✅ What to Do Instead:
  • Review your brokerage account settings and confirm whether cost basis tracking is enabled for all holdings — most brokerages now provide this for newer purchases.
  • For securities purchased before 2011 (when mandatory cost basis reporting began), maintain your own records: original confirmation slips, statements showing purchase dates and prices, and any DRIP reinvestment records.
  • If you have inherited securities, document the "step-up in basis" (the fair market value at the date of the original owner's death) as this is the cost basis you are entitled to use, potentially eliminating all taxable gain.